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Brucellosis is a contagious, infectious, and communicable disease affecting primarily cattle, bison, and swine that is caused by bacteria of the genus Brucella. Brucella abortus affects mainly bovine species; B. suis affects mainly porcine species. Goats, sheep, and horses are also susceptible to B. abortus. A third strain, B. melitensis, affects mainly goats and sheep. Though B. ovis, which affects sheep, does exist in the United States, it does not cause significant disease problems. Currently, there is no program and no initiative to establish a program for the control of B. ovis or B. melitensis

In its principal animal hosts, brucellosis causes loss of young through spontaneous abortion or birth of weak offspring, reduced milk production, and infertility. It can affect both animals and humans. Brucellosis is transmitted from animals by direct contact with infected blood, placenta, fetuses, or uterine secretions or through the consumption of infected and raw animal products (especially milk and milk products). There is no economically feasible treatment for brucellosis in livestock. 

The regulations of APHIS’ Brucellosis Eradication Program vary on the basis of the brucellosis status in each State. Minimum standards are set forth in the Brucellosis Eradication Uniform Methods and Rules, a publication distributed by VS. Some States have more restrictive requirements. Check with the APHIS –VS District Office nearest you  (appendix B) for testing and vaccination policies. Contact the State or Federal animal health officials in your State to obtain all necessary forms, mailers, identification tags, and other items required for both vaccinating and testing eligible animals. (For some items, fees may apply.) 

Interstate Shipment

Before testing for interstate shipment, obtain specific State regulations by contacting the State animal health official’s office in the importing State. See appendix C for a list of addresses and telephone numbers of State animal health officials. 

International Export

When preparing to test and certify an animal for international export, become familiar with the requirements by visiting the National Center for Import and Export, Animal Regulations Library at: and then contact the APHIS –VS District Office for additional guidance.

VS Form 4 – 33

VS Form 4–33, Brucellosis Test Record, must be completed for each animal or each herd tested (a separate 4–33 must also be completed for each species tested). See appendix D for an example of this form and instructions for completing it. VS Form 4–33 requires that you list the reason for the test. Reasons may include export (specify the test required by the importing country), interstate movement (depends on the State of destination), sale (even local change of ownership in many States), show or fair, diagnostic assessment (such as abortion), and owner request. If infection is suspected or confirmed, regulatory officials will contact you, the owner, or both, to develop a herd plan. 

VS Form 4 – 54

VS Form 4–54, Brucellosis Test Record—Market Cattle Testing Program, is used for brucellosis tests done as part of the Market Cattle Testing Program. That program refers to the testing of cattle and bison at markets (first point of concentration) or slaughter. See appendix D for an example of this form and instructions for completing it. 


Bovine—A complete herd blood test must include all cattle or bison 6 months of age and older, except steers, spayed heifers, official Strain 19 calfhood vaccinates of the dairy breeds under 20 months of age, and official Strain 19 calfhood vaccinates of bison or beef breeds under 24 months of age. The presence of the first pair of fully erupted permanent incisor teeth is evidence that an animal has reached 24 months of age. Official Strain 19 calfhood-vaccinated cattle or bison under these ages must be included in the herd test if they are parturient (springers) or have already calved.

Note: Age-based testing requirements do not apply to RB51 vaccinates. 

Swine—A complete herd test must include all breeding swine more than 6 months of age unless they are being fed for slaughter and are not in contact with breeding swine. Vietnamese potbellied pigs are considered to be domestic swine for the purposes of disease control and eradication procedures and, as such, fall under the same regulations in Title 9   of the CFR. All tested swine must be identified with an official eartag, tattoo, or other   official identification. Also see the subsection entitled “Current Animal Identification.”

Exotic Species—When dealing with exotic or nondomestic species, contact your State animal health official

or APHIS –VS District Office

Blood Collection and Submission

Identify each animal with either an official USDA metal eartag placed in the upper middle portion of the right ear, an official USDA RFID eartag placed in the middle of the left ear, an individual animal’s breed registration tattoo or brand, or an individual registration number (in conjunction with an official eartag, or breed registration tattoo or brand) issued by a breed association recognized by VS. (Also see the section entitled “Current Animal Identification.”) Record the eartag (identification or vaccination), registration tattoo, age (months or years), sex, and breed on VS Form 4–33. If you are working with a herd known to be, or suspected of being, infected, take proper precautions by wearing protective gloves and eyewear. Avoid direct contact with retained placenta, vaginal discharges, aborted fetuses, and other reproductive tissues because these materials are potential sources of human brucellosis.

Note: If the animal has an official USDA metal or RFID eartag in place, record that eartag on the 4-33, but do not place a new official USDA metal or RFID eartag in the ear. Record all official USDA eartags (metal and/or RFID). 

Collect 3 to 5 mL of blood. Take appropriate precautions to prevent hemolysis by (1) sending the samples with ice packs or (2) centrifuging, pouring the serum off, and sending the serum only. (See the section entitled “Laboratory Submissions.”) Because swine blood is particularly susceptible to hemolysis, take extra precautions in handling it. If you are bleeding the animal with a needle and syringe, do not extrude the sampled blood from the syringe through the needle into the test tube. This practice can cause hemolysis. Blood or serum samples should be delivered to the cooperative State or Federal laboratory as soon as possible for testing. Test results will be interpreted by State or Federal regulatory officials. You may be contacted for additional individual or herd history. 

Animals Eligible for Vaccination

Vaccinate only heifer calves between the ages of 4 and 12 months. Many States have even more restrictive age requirements for vaccination. Before vaccinating any animals for brucellosis, be certain that you understand and follow your State’s requirements. Adult vaccination for brucellosis is conducted by State and/or Federal officials only. If you have questions concerning this program, contact the State animal health official or the APHIS – VS District Office nearest you.

Instructions for Vaccination

Step 1: Vaccine Handling and Administration—

  1. Keep the vaccine stored properly according to label instructions.

  2. Check the expiration date before using.

  3. Reconstitute the vaccine following the label instructions.

  4. Mix the RB51 vaccine just before using; keep it cool and out of direct sunlight.

  5. Use caution. RB51 may cause clinical brucellosis in humans if accidentally injected, sprayed in the eyes, or allowed prolonged contact with the skin. If you are exposed, contact a physician as soon as possible.

  6. After reconstitution, the vaccine loses potency rapidly. Do not reconstitute more vaccine than will be used in 1 hour, and, if working in warm weather, keep the vial on an ice pack to maintain viability.

  7. To avoid contamination and accidental vaccine exposure to other than vaccination- eligible animals, maintain separate syringes and needles for brucellosis.

  8. Administer 2 mL of the vaccine subcutaneously. 

Step 2: Tattooing—

  1. Clean the inside of the right ear to enhance ink penetration. Green ink works best for legibility, especially in black-pigmented ears.

  2. Tattoo the ear with the appropriate coding between cartilage ribs in the middle of the ear. Allow for normal growth of the ear. If ear marks or notches do not permit this location, try to place the tattoo as near as possible to the recommended position.

  3. Apply the ink with a dauber and thoroughly rub the ink into the tattoo holes.

  4. Vaccination tattoos must be applied to the right ear. For B. abortus Strain 19 vaccinates, the tattoo will include the U.S. Registered shield and “V,” which will be preceded by a number indicating the quarter of the year and followed by a number corresponding to the last digit of the year in which the vaccination was done. For B. abortus Strain RB51 vaccinates, the tattoo will include the U.S. Registered shield and “V,” which will be preceded by a letter R and followed by a number corresponding to the last digit of the year in which the vaccination was done. Documentation of brucellosis vaccination tattoo information on the VS Form 4–33 and 4-54 is essential for accurate test interpretation.

  5. Below is an example of the tattoo that would be applied in the right ear of a female calf that was brucellosis vaccinated in the 3rd quarter of a year ending in the digit “2”. The first digit represents the quarter of the calendar year that the female calf was vaccinated in. The third digit represents the last digit of the 4 year digits of the year the female calf was vaccinated in. The middle digit is the Official Brucellosis Shield. In this example the calf was vaccinated in either July, August, or September and in either 1992, or 2002, or 2012, etc. For a female calf vaccinated with RB 51, the 3 would be replaced by an R, indicating vaccination with RB 51 in 1992, or 2002, or 2012. You should contact your State animal health official if you are interested in obtaining the Brucellosis Shield digit for your vaccination pliers.


 Example of a reduced dose vaccination tattoo applied in the right ear Step 3: Records—

  1. Record the information (eartag, age in months, breed, sex, and whether purebred or grade) on VS Form 4–24, Brucellosis Calfhood Vaccination Record, or VS Form 4–26, Brucellosis Vaccination Record. (See appendix D for examples and instructions for completing these forms.)

  2. Use only official USDA orange metal vaccination tags and official USDA tattoos placed in the right ear. Individual animal registered breed association registration brands or tattoos may be substituted for official eartags. Official USDA RFID eartags placed in the left ear, to avoid interference with the official vaccination tattoo, may be substituted for the official USDA orange metal vaccination tags.

  3. Promptly submit the vaccination records to your State program records offices as instructed by your State Officials. Many States require that records be submitted within 7 days; check with your State for specific guidelines. Note: Animals are not considered to be official vaccinates until the State animal health official or APHIS –VS District Office has recorded the certificate information. Timely submission of certificates is essential.

  4. On rare occasions, it may be necessary to recertify a vaccinated animal that has no tag or an illegible tattoo as having been vaccinated. Phone your State animal health official or APHIS –VS District Office for permission and specific instructions. 

Working With Infected Herds 

The details of eradicating brucellosis from herds known to be infected are beyond the scope of this manual. Your State animal health official, the APHIS –VS District Office for your State, and your local regulatory veterinarian will work with you and your client to develop a herd plan.

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